Surgically implanted flexible bag-type mammary prostheses have suffered a serious problem with the bag rupturing in certain cases after surgical implantation. This is believed to occur more frequently when the bag develops a crease. Several theories have been advanced to explain just why such a bag ruptures. Some believe it is due to the stress differential between inner and outer surfaces of a bag wall section and a crease area caused by one wall surface being in compression and the other being in tension. Others believe that this is caused by a change in the physical properties such as modulus, etc., over a prolonged period of maintaining a crease. Still others believe that the bag failures to be caused at least in part by friction between opposing wall sections in a fold area. This latter view is explained in Rees et al. in "The Use of Inflatable Breast Implants," Plastic and Reconstructive Surgery, Volume 52, Number 6, December 1973, pp. 609-615.
This type of bag wall failure in a creased area has been known for many years as "fold flaw." All of the mechanisms explained above may contribute in causing fold flaw failure. Heretofore, a solution to reduce fold flaw failure has not existed.